Diagnostic and therapeutic work carried out in the first four years of this grant has lead to the isolation of a specific group of insomniacs (tentatively labeled idiopathic). Some of these idiopathic insomniacs seem to be characterized mainly by increased muscle tension and arousal; others show various atypical EEG stages (e.g., excessive alpha intrusion into sleep, lack of sleep spindles during stage 2, etc.). Biofeedback training of the sensorimotor rhythm carried out in the first three years of this grant seems to improve the sleep of some of these patients. The study is currently in the midst of collecting a new sample of 100 insomniacs and 10 good sleepers to replicate and refine the earlier findings. Besides standard sleep parameters, the amount of alpha intrusion into sleep, the amount of SMR activity during waking and sleeping, and the level of tonic frontalis EMG during waking and sleeping are measured. Factor analysis of these data, combined with interview and psychological testing, should indicate whether the nosology of idiopathic insomnia developed earlier is valid. A subsample of 30 idiopathic insomniacs receives either SMR biofeedback or theta biofeedback. Each of these 30 patients sleeps in the laboratory for three nights, twice more: immediately following biofeedback, and 9 months later. Data collection for this grant should be finished within about one year; results should be available late in 1979.